The invention relates to plastic moldings prepared from optionally filled polyurethanes which exhibit high tenacity, flexural strength and heat stability. The present invention also relates to a process for the preparation of these plastic moldings, and to the production of large molded parts from these.
U.S. Pat. No. 4,299,924 describes a process for the production of polyisocyanurate (PIR) plastics which have a high heat stability, a high tenacity and a high flexural strength. The polyol component used consists of polymeric polyols modified by ethylenically unsaturated monomers such as styrene, acrylonitrile, etc. The polyols are processed with a high excess of isocyanate or high indices in order to produce the plastics. As a result, the volumetric flow rates are several times greater on the isocyanate side than on the polyol side, which leads to considerable production engineering problems.